Iranian Journal of Rangelands and Forests Plant Breeding and Genetic Research
Year:2006 | Volume:14 | Issue:1 (23)|Papers Count:7

Loliul1l species have different characteristics. Interspecific hybridization would facilitate the integration of valuable characteristics into one variety. In this regard several interspecific hybrid plants were produced between Loliul1l perenne and L. rigidum through embryo rescue. For verification of hybridization four interspecific hybrids along with their parents were investigated for their karyotypic characteristics. There was a vast variability in chromosome number in the hybrids. To detect the differences between the genotypes and their chromosomes the data were analyzed in a factorial statistical model with the base design of completely randomized design. The differences between the numbers of chromosomes in the hybrids indicated the incompatibility between the genomes of the two parents as well as confirming the hybridization. On the other hand, this phenomenon is common in L. rigidul1l which was used as the male parent. It seems this phenomenon was a heritage from the male parent. A number of parameters were estimated to investigate the karyotypic symmetric of the genotypes whose TF% indicated that one of the parents (P1) has the most asymmetric karyotype and one of the hybrid genotypes (L3) has the most symmetric karyotype.

In order to determine the response of 3 annual clover species (6 variety) against drought stress, an experimentwith3 replications was conducted in randomized completely design as factorial in 2004.The treatments included, two species and four sub species of clover and four levels of osmotic potential (0, - 0.3, -0.7 and-1.1 Mpa) that were made by poly ethylene glycol (PEG 6000) solution. The measured characteristics were germination percentage, length and dry weight seedling, radicle and hypocotyl dry weight and radicle to hypocotyls length ratio. Species showed significant differences (P<0.01) for all the characteristics at germination under drought stress. In this research, Varamin species (T. alexandrinum var. carl1lel and T. resupinatum (Arak haft chin) in the most measured factors were more tolerant than the others. T. resupinatum (Kordestan do chin) and (Abadeh Sorrian) were introduced as semi-tolerant species. T. subterraneum var. clark) and T. resupinatum (Kazeroon baladeh) were the most sensitive to drought stress, because they had the lowest value in measured factors.

The objectives of this experiment were to study genetic variation and relationships among 11 traits in 23 accessions of Agropyron elongatum for two years. The experiment was conducted in Agricultural Biotechnology Research Institute of Central region of Iran research farm using a randomized complete block design with 3 replications. Results of variance analysis showed significant differences between the accessions for all of the traits in the first year and most traits in the second year. The results also showed that there was considerable phenotypic and genotypic variation for forage yield and number of stems per plant.Broad-sense heritability was high (63-84%) for forage yield, days to heading, crown diameter and plant height. Forage yield per plant had a significant (P<0.01) negative correlation with days to heading (r=-0.53) and days to pollination (r=-0.64), but a significant (P<0.01) positive correlation with plant height (r= 0.33), flag leaf width (r=0.41), numberof stems (r=0.6) and crown diameter(r=0.4).

Correlation coefficient indicates only size and sign of relationship between traits. Path analysis can determine direct and indirect effects. Thus, plant breeders use path analysis to identify effective traits on yield. An investigation was conducted in unbalanced CRD including 27 genotypes (7 Poa species) collected from different parts of Zanjan province. Significant relationship was found by simple correlation coefficient among yield and traits, including spike weight, stem weight, spike length, pollination date, flowering date, stem number and leaf to stem ratio. After regression analysis, number of effective traits reduced to four traits, including spike weight, fresh forage weight, crown diameter and plant height. Final equation explained 96 percent of total variation. Eventually, path analysis showed that spike weight and fresh forage weight had the most direct effect on yield.

In order to determine the best method of seed hardening, an experiment was carried out in greenhouse stages in the format of split - split plot design. First factor including four levels of drought stress (100% FC, 75% FC, 50% FC, 25% FC) and second factor including 4 genus (Vicia villosa, Onobrychis sativa, Trigonella foenum and Lens culinaris), and third factor including resistance method in five levels (CuSo4, ZnSo4, B, control, alternative watering). Four physiological characteristics root and shoot lengths and root and shoot fresh weights were evaluated. Treatments showed significant differences for most of the traits. Treatment of alternative watering and drying in Trigonella had the most effect. Comparison of treatments showed that Onobrychis, Vicia, Trigonella and Lens demonstrated better growth under treatments and also CuSo4, Band ZnSo4 has effected respectively in induction of gradual consistency of seeds to drought stress.

Intensive human activities such as urban, industrial, agriculture and traffic leads to indirect destruction of the human environment such as air pollution, water table contamination,... by pesticides, nitrates, organic contaminants and heavy metals. In such areas use of plants that have the capability to store the heavy metals can be economically effective. This research was carried out to estimate the effects of four heavy metals (Cu, Zn, Cd, Pb) on three Eucalyptus species, including E. camaldulensis, E. microtheca and E. occidentalis. 16 treatments (every metal in 3 levels combination of 4 metals in 3 levels and control) in a factorial design in base of completely randomized design in a growth chamber was carried out. One way analysis of variance used to verify significance of 16 treatments on 6 characters such as height of radicle, height of plumule, vigor index, germination percentage, speed of germination and germination index, for each species. The result showed that the effects of the treatments and their interactions on seed and seedling characters were significant, except of the interaction on seed germination. The species performed different seed germination and seedling growth characters under different levels of heavy metals. Duncan analysis was used for classification of data. Results showed that E. microtheca had the greatest values of vigor index, germination speed, germination index, germination percentage and radicle length.

Five Artemisia species, including Artemisia scoparia, A. oliveriana, A. persica, A. aucheri and A.biennis were collected from Kashan, Iran. Apical meristem of seed radicles were prepared and mitotic cells for the karyotypic attributes at metaphase stage were measured. Different ploidy leveles were observed; the species. Artemisia scoparia, A. persica, A. biennis were diploid, while A. aucheri was tetraploid and A. oliveriana was hexaploid. The base chromosome number was x=8 or x=9. Several karyotypic symmetric parameters were estimated and Karyotipic idiograms of the species were also presented. The species showed nearly symmetric karyotypes. Polyploidy species had less karyotipic symmetry than diploids. Polyploid species belonged were collected from drought area, but diploid species were collected from marginal brooklets of studied Areas, while A. oliveriana was collected from dried and brackish habitats.